Screen.



PATBNTED FEB. 12, 1997.

No. 843,785.l

I 0.9. ALLEN.

SCREEN.

APPLIGATIDN FILED DB9. 19. 1995.

A TTORZVEY v WYTNESSES:

TINTTE ll- STATES PATENT FFTCE.

SCREEN.

Specication of Letters Patent.

Patented Feb. 12, 1907'.

Application led December 19, 1905. Serial No. 292,476.

To @ZZ whom t may concern.-

Be it known that I, CHARLES R. ALLEN, a citizen of the United States, residing at San Francisco, in the county of San Francisco The object of the invention is to provide a.

screen which can be constructed economically and durably and which will have a large capacity with maximum efficiency.

An embodiment of the invention is shown in the accompanying drawings, in whichh Figure l is a perspective view. Fig. 2 is a plan view, and Fig. 3 is an end view.

Broadly considered, my improved screen comprises two parts or sections l and 2, each of which consists of side pieces 3, cross-pieces 4, and longitudinal slats or bars 5. 'Both sections are inclined longitudinally, one above the other, with the lower end of the upper section overlapping the upper end of the lower section and preferably iitting between its side pieces. Each of the crosspicces is bent so as to form an angle 6 substantially at its middle, the bend of those of the upper section being above the side pieces, so as to make the screening-surfaces incline outwardly or roof-shaped, and those of the lower section being below the side pieces, so as lto make the screening-surfaces incline inwardly or trough-shaped. The bars are secured to the cross-pieces in any desired manner and are at such a distance apart as is necessary to effect the desired result in grading or screening any articles or product.

In using a screen as above described the two sections are supported in any desired manner and at any desired pitch or angle of inclination. The material is fed upon the upper end of the upper section from any suitable source of supply, which is not shown, as it is of the ordinary construction and forms no part of the invention. From there the material passes diagonally downward upon each side until it engages with the side pieces or falls oii the lower end; but in either case it passes on to the upper end of the lower section at or near the side pieces and then passes diagonally7 downward and inward until it reaches the center of the section or bottom of the trough, whence it passes to the lower end and is discharged. In its passage down the sections in this manner it is evident that in passing Jfrom one bar to the other laterally or toward the side pieces the material will have a tendency to roll or move longitudinally of the bar before passing over it, and consequently it is given a greater opportunity to pass through and be screened out than if it were caused to pass over the opening in a straight or direct line, as with the usual construction of screensurfaces. In this manner the capacity of the screen will be very great and the screening or separation will be very close, and both -results may be changed or varied by changing the length of the sections or the inclination, either laterally or longitudinally, or all of them, and instead of making the bends in the cross-pieces angular they can be made gradual, whereby the screening-surfaces are curved in cross-section as convex or concave instead of roof and trough shaped, respectively.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

In a screen, two inclined sections arranged endbto end one above the other, with their adjacent ends overlapping and each section comprising side pieces, cross-pieces and longitudinal bars, the cross-pieces being bent so as to hold the bars in oppositely-arranged in-.

clined planes, those of the upper section being roof-shaped and those oi' the lower section trough-shaped.

In testimony whereof I have a'HiXed my signature, in presence of two witnesses, this 29th day of November, 1905.

CHARLES R. ALLEN.

l/Vitnesses:

M. R. SEELY, F. M. BARTEL. 

